Talk given in the Space in the City series "Mammon's Revenge", at the United Church, Winchester, England on 17 March 2010. The talk, which lasts 30 minutes, is introduced by Debbie Thrower who then chairs a 15-minute question-and-answer. www.spaceinthecity.org.uk (Note: at the first question from the floor, at about 31 minutes, there was a fault with the floor microphone. This was corrected during the answering of that question, about one minute later.)